An adaptive cruise control (ACC) system is a system that enables a vehicle to be autonomously driven at a velocity set by a driver and maintains an appropriate inter-vehicle distance by measuring an inter-vehicle distance in real time through a laser sensor mounted in the front of a vehicle to assist safety driving of the vehicle by maintaining a safety distance from a preceding vehicle without a driver repeatedly operating an acceleration pedal and a brake pedal.
In recent years, the ACC system interlocks with a driving path setting system such as a navigation, and the like positioned in the vehicle, and as a result, the ACC system can set a target velocity profile for improving fuel efficiency by considering road information on a driving path.
The ACC system performs driving with the set target velocity profile when there is no preceding vehicle and when the preceding vehicle is discovered, the ACC system prevents a collision with the preceding vehicle by performing deceleration driving in order to maintain a predetermined distance from the vehicle.
As a related art, there is a cruise control system which can reduce fuel consumption while appropriately maintaining the safety distance between the vehicles and provides a technical characteristic that controls the vehicle according to the inter-vehicle distance by calculating a velocity variation by using a velocity profile.
FIG. 1 illustrates an adaptive cruise control system adopting an inter-vehicle distance by calculating a velocity variation by using a velocity profile in the related art. Referring to FIG. 1, compared with a running curve V of a preceding vehicle, a velocity profile S is not the same type, but has a type that the velocity profile S may ensure fuel efficiency while following the preceding vehicle. When a distance between the preceding vehicle and an own vehicle is greater than a preset first reference distance A, variation in velocity is calculated using the velocity profile. The velocity profile follows the speed of the preceding vehicle to reduce the distance between the vehicles (A represents a reference distance between a velocity profile and a preceding vehicle, B represents a distance between the own vehicle and a preceding vehicle, S represents a running curve of the velocity profile, R represents a running curve of the own vehicle, and V represents a running curve of the preceding vehicle).
However, as described above, when the preceding vehicle is discovered and the vehicle decelerates through braking in order to maintain the inter-vehicle distance at a predetermined distance or more, driving different from a target velocity profile initially set to improve the fuel efficiency is performed and inflexible control in which acceleration or deceleration control is frequently performed cannot but be performed, and as a result, the fuel efficiency deteriorates.
As described above, in the related art, a control method is performed, which controls an engine output or braking force of the vehicle based on the velocity variation through the velocity profile of the vehicle, and as a result, a separate fuel efficiency driving profile depending on the changed velocity of the vehicle cannot be provided.
Further, as a method responding to various distance variations, a configuration of deceleration-controlling the velocity of the vehicle through braking is just provided, and as a result, it is impossible to respond to a request by a user for fuel efficiency driving.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.